I've tried some bluegrass banjo Ray. I've a book by Peter Wernick that takes you from beginner to upper-intermediate (R220 on Loot:
http://www.loot.co.za/product/peter-wernick-bluegrass-banjo-wernick/tfsv-241-g990). I haven't got much past the first couple of chapters ? This is partly because my banjo was appallingly bad (stay clear of Hondos - which is advice that goes for more than banjos). But it's partly because bluegrass banjo is pretty damn hard.
There are a couple of differences from guitar. You always use fingerpicks. That takes some getting used to, but it's essential to the snappy style of Scruggs-style playing. You use two fingers and thumb which takes getting used to if like me you use three fingers and thumb (and sometimes the pinky too) for guitar finger-picking. You've got that repeat high G string as the 5th string which isn't connected to the nut. This plays a part in what really takes some getting used to.
Basically, at its simplest, in this style you have to choose rolls based on which melody notes you want to play - so that you can get the melody to come out through the flurry of notes. This takes, in my experience, a lot of practise. To be able to take a song like, say, Grateful Dead's Ripple, and be able to not just follow the chords, but make the melody come out too. That's the basic trick to bluegrass banjo from what I can understand. The rest is learning how to do the fills, playing higher up the neck. Pauses. Bends. Slides. Hammer-ons. All that malarkey.
There's a guy (listen up everybody)
playing with a group every second sunday at Touch of Madness in Observatory - and who'll be there next Sunday with a guitar player and an upright bass player - (not going to help Ray) who can just freakin' rip. I was meaning to ask him what he thinks I should look out for in a banjo for under R5K. I'll be sure to do so next Sunday.
The shops have Fenders and Washburns. The Washburns look ok while the Fenders seem a bit cheap and cheerful for the price. I bet you can really score second hand though.